Well drill bit



'A Patented Aug. 1935 UNITE-D lSTATES PATENT OFFICE mmajtil'..t.

e claims. (onzas-c1) This invention relates to new and useful improvements in well drill bits..

One object of the Yinvention is to provide an improved drill bit of thedetachable cuttertype. A particular object of the invention is toprovide an improved drill bit having a cutter fastening entirely housedin the head or body, whereby the cutter is more securely fastenedlandiso long as the head remains connected to the drill stem l thefastening cannot become disenaged from the cutter.

A further object of thel invention is to provide an improved cutterblade fastening which will be self-tightening.

Another object of the invention is to provide an improved drill bitcomprising a body or head having a socket in its upper end receiving thecutter shank and a fastening in said socket engaging the shank andconiln'ed by the drill stem or pipe. connection which is engaged in saidsocket, whereby said fastening can only be disengaged by rst removingthe drill stem or. pipe connection from the socket.

Still another object ofthe invention is to provide a drill bit in whichshort uld ducts are provided and which deliver iluid close to thecutting edge of the blade; and also wherein theV cutter fastener issealed oif from the iluids ilowing through the body. f

A construction designed tocarry out the invention will be hereinafterdescribed, together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawing inwhich an example of the invention is shown, and wherein: 4

Figure l is a view partly in elevation and partly in vertical section,showing a drill bit constructed in accordance with the invention,

Figure 2 is a transverse vertical sectional view of the same, l

Figure 3 is a plan view, the sealing disk and key being omitted,

Figure 4 is a plan view of the sealing disk,

. Figure 5l is an. enlarged side elevation ofthe key, 'and Figure 6 isan elevation of the same.

In,.the drawing the numeral Il designates a head or body which may haveany suitable shape, but which is preferably cylindrical at its upper endand wedge-shaped toward its lower end. v An elongated transverse openingII is provided in the lower end of the head and an upwardly convergingslot I2 extends from said opening. The

mm the opening 26 end and side walls of the slot are inclined toward thecenter of the head. The sides of the opening I I are given the samevinclination as the slot. An

internally screwthre'aded pin socket Il is formed inthe upper end of thehead. 5

A cutter blade I4 -is provided with a wedgev shaped shank I5 'having asnug sliding fit upwardly-in the opening `II and slot I2. The blade hasoppositely curved cutters I6' contiguous to the lower end of the. head.'The blade also has shoul- 10 ders I'l at each side engaging in socketsIl at each end of the opening II, whereby the blade is braced againsttorsional strains and is less likely to be twisted from its shank Il.

At the bottom of the socket I3 a curved seat or 15 sump I9 is providedat substantially right angles to the shank which has a rectangularopening 20 registering with said seat. A curved or crescent-shaped key2| fits in said seat and passes through the opening 20 for fastening theblade in 20 the head. The key has a flat head 22 and a blunt point 23,being gradually reduced from its head to its point.

The top of the opening 20 is transversely rounded so that the key may bemore readily 25 drivento draw the shank I5 into the slot I2. It is'obvious that the curved seat will guide the key and it is only necessaryto start the point downwardly and slide the key into place. Thecurvatures will assist in positioning the key and it is only necessaryto tap the head 22 to tightly fasten the parts. Owing to the convergingshape of the shank I5v and the curvature of the seat I it will be seenthat as the shank IS is driven up into the socket by the imposed weight,when the cutters are on bottom, said key will slide in its seat intomore intimate engagement with the shank, thus being self-tightening;

A sealing disk 24 fits in the bottom of the socket I3 so as to'seal offthe seat I9. The disk has 40 nipples 25 extending therethrough andtelescoping the upper ends of iluid ducts 26 extending from the bottomof the socket on each side of the seat to the lower edge of the head oneach side of the opening II. The disk is provided with an eye 21 whichmay be engaged to lift it from the socket. Y' 1 The disk seals of! theseat I9 from the uids delivered to the socket from the pin of the drillstem (not shown). These fluids are conducted through the nipples 25 tothe ducts 2i. rThe disk also holds the key 2| in the seat. The shortducts .2l are important and their delivery of the nuids at the cuttersis an advantage over` those which discharge higher up the blade. Thecloser to the cutters the discharge, the more eective is the washing.

It is obvious that so long as the seat i 9 is sealed ci by the disk 2d,the key 2 i' cannot be disengaged fromrthe shank i5 and the key beingentirely housed Within the head is protected and held in place. It wouldbe possible to omit the disk and have the pin hold the key in the seat.The key is easily installed or'removed, but cannot be lost in the well.vThe particular construction of the cutter blade. is unimportant and maybe changed for diierent kinds of drilling.

`The description which has been given recites more or less detail of aparticular embodiment of the invention, which is set forth as new andusc-- ful; however, I desire it understood that the invention is notlimited to such exact details of construction, because it is manifestthat changes and modifications may be made, within the scope of theappended claims, without departing from the spirit or the invention.VVihat l claim and desire to secure by Letters Patent, is:

l. A Well drilling bit comprising, a body having a socket therein, aseat at the bottom oi the socket, a cutter having its shank extending tosaid seat, a key mounted in said seat and engaging said shank, and asealing member covering the seat and key at the bottom cf the socket.

2. A. Well drilling bit comprising, a body having a socket in its upperend and-an opening extending axially of the body up to the socket, acutter having its shank engaging in said body opening, a fasteninginserted through said socket and engaging said shank to hold said shankin the body, the body having ducts extending from the socket downwardlyto the cutter, and a sealing member at ther bottom of said socketcovering aoidaae the fastening and having openings registering with saidducts.

' 3. A well drilling bit comprising, a body leaving a socket in itsupper end and an opening extending axially of the body up to the socket,a cutter having its shank engaging in s icl body opening, a transverselycovered seat at t e bottom of the socket intersected by the shank, anda. curved key mounted in said seat and passing through said shank.

. t. A well drilling bit comprising, a body having a socket inits upperend and an opening extending axially of the body up to the socket, acutter having its shank engaging in said body opening, a transverselycovered seat at the bottom of the socket intersected by the shank, acurved key mounted in said seat and passing through said shank, and adisk at the bottom of the socket covering the seat and key.

5. A well drilling bit comprising, a head having a screw-threaded pipesocket in its upper end, a

cutter mounted at the lower end of the head and having its shank rigidlyhoused in the head and exposed to the socket, a fastening insertableonly through the socket and engaging said cutter shank for rigidlyfastening said shank in said head, and a sealing member at the bottom ofsaid. socket covering the cutter shank and the fastening.

6. A lwell drilling bit comprising, a head having a. screw-threaded pipesocket in its upper end, a transverse seat at the bottom of the socket,a cutter at the bottom of the head, a shank rigid in the head extendingfrom the cutter through said seat, and a transverse key insertablethrough said socket into said seat and engaging said shank for fasteningit in said head.

' RICHARD F. JOHNSON.

